1. Field of the Invention
This invention relates to an intercom apparatus and, more specifically, to an intercom apparatus having a terminal unit which can be separated from an intercom master station.
2. Related Art
A conventional intercom apparatus (see, FIG. 1) has one or more entrance substations and a plurality of intercom master stations respectively located in residential rooms and called from the entrance substation through a main communication line for bilateral communication with the entrance substation. A terminal base is disposed at the backside of the intercom master station and electrically connected to a board formed integrally with the intercom master station.
In such an intercom apparatus wiring coming from the residential room is directly connected to the terminal base disposed at the backside of the intercom master station and to the intercom master station in the next residential room, and intercom master stations in respective residential rooms are connected in sequence.
In the intercom master station of the above-described intercom apparatus of the related art, there is the drawback that it can not be applied where main bodies of the intercom main station do not exist at an installation location. Further, since the main bodies of the intercom master station must be wired, it is hard to make the wire connection and there is the possibility that the apparatus may be dropped and broken carelessly. Furthermore, if the intercom master station is broken or has a defect requiring maintenance, that entire intercom master station must be disconnected and, by removing one intercom main station from the main communication line, the entire intercom system is disabled.
Moreover, since during the period between installation and occupancy, the main bodies of the intercom master station can not be moved, there is a drawback that they are can become dirty in the installation location, and there is the possibility that intercom master stations may be stolen from the installation locations during that period.